function SHA1(msg) {

	function rotate_left(n, s) {
		var t4 = (n << s) | (n >>> (32 - s));
		return t4;
	};

	function lsb_hex(val) {
		var str = "";
		var i;
		var vh;
		var vl;

		for (i = 0; i <= 6; i += 2) {
			vh = (val >>> (i * 4 + 4)) & 0x0f;
			vl = (val >>> (i * 4)) & 0x0f;
			str += vh.toString(16) + vl.toString(16);
		}
		return str;
	};

	function cvt_hex(val) {
		var str = "";
		var i;
		var v;

		for (i = 7; i >= 0; i--) {
			v = (val >>> (i * 4)) & 0x0f;
			str += v.toString(16);
		}
		return str;
	};


	function Utf8Encode(string) {
    // string = string.replace(/\r\n/g, "\n");
    var utftext = "";

    for (var n = 0; n < string.length; n++) {

    	var c = string.charCodeAt(n);

    	if (c < 128) {
    		utftext += String.fromCharCode(c);
    	}
    	else if ((c > 127) && (c < 2048)) {
    		utftext += String.fromCharCode((c >> 6) | 192);
    		utftext += String.fromCharCode((c & 63) | 128);
    	}
    	else {
    		utftext += String.fromCharCode((c >> 12) | 224);
    		utftext += String.fromCharCode(((c >> 6) & 63) | 128);
    		utftext += String.fromCharCode((c & 63) | 128);
    	}

    }

    return utftext;
};

var blockstart;
var i, j;
var W = new Array(80);
var H0 = 0x67452301;
var H1 = 0xEFCDAB89;
var H2 = 0x98BADCFE;
var H3 = 0x10325476;
var H4 = 0xC3D2E1F0;
var A, B, C, D, E;
var temp;

msg = Utf8Encode(msg);

var msg_len = msg.length;

var word_array = new Array();
for (i = 0; i < msg_len - 3; i += 4) {
	j = msg.charCodeAt(i) << 24 | msg.charCodeAt(i + 1) << 16 |
	msg.charCodeAt(i + 2) << 8 | msg.charCodeAt(i + 3);
	word_array.push(j);
}

switch (msg_len % 4) {
	case 0:
	i = 0x080000000;
	break;
	case 1:
	i = msg.charCodeAt(msg_len - 1) << 24 | 0x0800000;
	break;

	case 2:
	i = msg.charCodeAt(msg_len - 2) << 24 | msg.charCodeAt(msg_len - 1) << 16 | 0x08000;
	break;

	case 3:
	i = msg.charCodeAt(msg_len - 3) << 24 | msg.charCodeAt(msg_len - 2) << 16 | msg.charCodeAt(msg_len - 1) << 8 | 0x80;
	break;
}

word_array.push(i);

while ((word_array.length % 16) != 14) word_array.push(0);

word_array.push(msg_len >>> 29);
word_array.push((msg_len << 3) & 0x0ffffffff);


for (blockstart = 0; blockstart < word_array.length; blockstart += 16) {

	for (i = 0; i < 16; i++) W[i] = word_array[blockstart + i];
		for (i = 16; i <= 79; i++) W[i] = rotate_left(W[i - 3] ^ W[i - 8] ^ W[i - 14] ^ W[i - 16], 1);

			A = H0;
		B = H1;
		C = H2;
		D = H3;
		E = H4;

		for (i = 0; i <= 19; i++) {
			temp = (rotate_left(A, 5) + ((B & C) | (~B & D)) + E + W[i] + 0x5A827999) & 0x0ffffffff;
			E = D;
			D = C;
			C = rotate_left(B, 30);
			B = A;
			A = temp;
		}

		for (i = 20; i <= 39; i++) {
			temp = (rotate_left(A, 5) + (B ^ C ^ D) + E + W[i] + 0x6ED9EBA1) & 0x0ffffffff;
			E = D;
			D = C;
			C = rotate_left(B, 30);
			B = A;
			A = temp;
		}

		for (i = 40; i <= 59; i++) {
			temp = (rotate_left(A, 5) + ((B & C) | (B & D) | (C & D)) + E + W[i] + 0x8F1BBCDC) & 0x0ffffffff;
			E = D;
			D = C;
			C = rotate_left(B, 30);
			B = A;
			A = temp;
		}

		for (i = 60; i <= 79; i++) {
			temp = (rotate_left(A, 5) + (B ^ C ^ D) + E + W[i] + 0xCA62C1D6) & 0x0ffffffff;
			E = D;
			D = C;
			C = rotate_left(B, 30);
			B = A;
			A = temp;
		}

		H0 = (H0 + A) & 0x0ffffffff;
		H1 = (H1 + B) & 0x0ffffffff;
		H2 = (H2 + C) & 0x0ffffffff;
		H3 = (H3 + D) & 0x0ffffffff;
		H4 = (H4 + E) & 0x0ffffffff;

	}

	var temp = cvt_hex(H0) + cvt_hex(H1) + cvt_hex(H2) + cvt_hex(H3) + cvt_hex(H4);
	return temp.toLowerCase();

}

export {
	SHA1
}